The invention relates to an absorber body with flow paths for water or a flowable heat carrier for the direct or indirect heating of fluid or fluids or the like flow agents by solar energy, in which the flow paths are produced by the deformation of plastic material. The invention also concerns a process which is particularly suitable for the production of the absorber body.
So-called solar heating systems use energy storage means which comprise for example rubber mats in which tubular flow routes receive cold water from a feed pipe and pass it to a return in those flow routes, with the water being heated by incident solar radiation. Absorbers of that kind are used in particular for the direct heating of swimming pool water which is usually circulated by means of pumps.
In contrast to that mode of direct heating of water for industrial use, indirect systems require a fluid heat carrier such as water which is possibly mixed with an antifreeze agent and which flows through the pipe system, which covers a certain area, in a closed circuit. In a heat exchanger, the fluid heat carrier gives off its energy to a related water circuit, while accepting losses.
Solar collectors are generally installed at an inclined angle, for example on a roof surface, and, with increasing temperature, their heat carrier is driven upwardly in a natural circuit (thermosiphon effect) to an heat exchanger disposed at the upper end of the collector surface, in order to flow downwardly again after having given off energy.
Those collectors which are exposed to the effect of the sun may have separating walls which extend between two parallel surfaces transversely with respect thereto, to define the flow path, or they may have tube portions which are formed at a surface thereof, the parallel mouth openings of which are connected together by respective transverse tubes so that they can be connected to feed and return means.
The materials used for the flow paths should be resistant to weathering, temperature and chemicals, that is to say they should be resistant to aging. Particularly, in the case of indirect systems for roof installation, the influence of weathering can be reduced by having the surface structures through which ducts pass and which are made from synthetic rubber such as polymerized ethylenes and propylenes disposed in a housing beneath a glass plate or panel which at the same time can cause an accumulation of heat in the housing.
A disadvantage of known absorber mats and bodies is their comparatively expensive manufacture, while a further deficiency, in the case of indirect heating systems, in particular for swimming pools, lies in the fact that the water at least retains its undesirable load of bacteria while it passes through the collector.